The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the

right atrium The atrium (; : atria) is one of the two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves. ...

of the

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

. It is formed by the joining of the right and the left

common iliac vein In human anatomy, the common iliac veins are formed by the external iliac veins and internal iliac veins. The left and right common iliac veins come together in the abdomen at the level of the lumbar vertebrae, fifth lumbar vertebra, forming the ...

s, usually at the level of the fifth lumbar vertebra. The inferior vena cava is the lower (" inferior") of the two venae cavae, the two large

vein Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and feta ...

s that carry deoxygenated blood from the body to the right atrium of the heart: the inferior vena cava carries blood from the lower half of the body whilst the

superior vena cava The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vei ...

carries blood from the upper half of the body. Together, the venae cavae (in addition to the

coronary sinus The coronary sinus () is the largest vein of the heart. It drains over half of the deoxygenated blood from the heart muscle into the right atrium. It begins on the backside of the heart, in between the left atrium, and left ventricle; it begi ...

, which carries blood from the muscle of the heart itself) form the venous counterparts of the

aorta The aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the Ventricle (heart), left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at ...

. It is a large retroperitoneal vein that lies posterior to the

abdominal cavity The abdominal cavity is a large body cavity in humans and many other animals that contain Organ (anatomy), organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roo ...

and runs along the right side of the

vertebral column The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmente ...

. It enters the right auricle at the lower right, back side of the heart. The name derives from .

Structure

The IVC is formed by the joining of the left and right

s and brings collected blood into the

of the heart. It also joins with the azygos vein (which runs on the right side of the vertebral column) and venous plexuses next to the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

. The inferior vena cava begins as the left and right common iliac veins behind the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

unite, at about the level of L5. It passes through the thoracic diaphragm at the caval opening at the level of T8 - T9. It passes to the right of the descending aorta.

Tributaries

The specific levels of the tributaries are as follows: Because the inferior vena cava is located to the right of the midline, drainage of the tributaries is not always symmetrical. On the right, the gonadal veins and suprarenal veins drain into the inferior vena cava directly. On the left, they drain into the renal vein which in turn drains into the inferior vena cava. By contrast, all the lumbar veins and hepatic veins usually drain directly into the inferior vena cava.

Development

In the

embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

, the inferior vena cava and right auricle are separated by the valve of the inferior vena cava, also known as the ''Eustachian valve''. In the adult, this valve typically has totally regressed or remains as a small fold of endocardium.

Anatomy variations

The anatomy of the IVC can exhibit abnormalities in approximately 8.7% of the global population. These variations may arise during its development, specifically between the 4th and 8th weeks of gestation, due to the intricate process of vessel formation. The IVC is composed of four segments formed from the anastomoses of various vessels: hepatic, suprarenal, renal, and infrarenal. The hepatic segment originates from the vitelline vein, while the suprarenal segment includes a portion of the right subcardinal vein that does not regress. The renal segment is created through the anastomoses of the right suprasubcardinal and postsubcardinal veins, and the infrarenal segment derives from the right supracardinal vein. The subcardinal and supracardinal veins gradually replace the postcardinal veins, which persist as the common iliac veins within the pelvis. The formation of the IVC is a complex process that can result in anomalies. These anomalies are more frequently observed in individuals with other cardiovascular defects. The most common variants are the duplicated IVC and left IVC. In a duplicated IVC, both supracardinal veins persist, a rare variant affecting 0.2–3% of the population. Most of these anatomical variations are asymptomatic, but their identification is crucial for the accurate planning of complex surgeries to avoid complications. Ultrasound (US) systems are typically used to identify these variations; however, other techniques such as computed tomography (CT), which involves ionizing radiation, or magnetic resonance imaging (MRI), which is more costly, are often preferred due to the user-dependent nature of US analysis. In between 0.2% to 0.3% of people, the inferior vena cava may be duplicated beneath the level of the renal veins.

Function

The inferior vena cava is a

. It carries deoxygenated blood from the lower half of the body to the

of the

. The corresponding vein that carries deoxygenated blood from the upper half of the body is the

Diameter evaluation of IVC

Various image-processing methods have been applied to US scans of the IVC. The number of algorithms is slightly larger for the analysis of transverse than longitudinal view. This may stem from the fact that it is easier to segment a closed cross-section than an open long-axis portion of the IVC, as the latter requires careful tracking of the region of interest. In recent years, deep learning approaches are gaining more importance, so that further developments are expected in the future in such a direction.

Clinical significance

Health problems attributed to the IVC are most often associated with it being compressed (ruptures are rare because it has a low intraluminal

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...

). Typical sources of external pressure are an enlarged

(

abdominal aortic aneurysm Abdominal aortic aneurysm (AAA) is a localized enlargement of the abdominal aorta such that the diameter is greater than 3 cm or more than 50% larger than normal. An AAA usually causes no symptoms, except during rupture. Occasionally, abdo ...

), the gravid

uterus The uterus (from Latin ''uterus'', : uteri or uteruses) or womb () is the hollow organ, organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic development, embryonic and prenatal development, f ...

( aortocaval compression syndrome) and abdominal malignancies, such as

colorectal cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the Colon (anatomy), colon or rectum (parts of the large intestine). Signs and symptoms may include Lower gastrointestinal ...

, renal cell carcinoma and ovarian cancer. Since the inferior vena cava is primarily a right-sided structure, unconscious pregnant women should be turned on to their left side (the recovery position), to relieve pressure on it and facilitate venous return. In rare cases, straining associated with defecation can lead to restricted blood flow through the IVC and result in syncope (fainting). Blockage of the inferior vena cava is rare and is treated urgently as a life-threatening condition. It is associated with

deep vein thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enl ...

, IVC filters, liver transplantation and surgical procedures such as the insertion of a

catheter In medicine, a catheter ( ) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. ...

in the femoral vein in the

groin In human anatomy, the groin, also known as the inguinal region or iliac region, is the junctional area between the torso and the thigh. The groin is at the front of the body on either side of the pubic tubercle, where the lower part of the abdom ...

.Geehan DM, Inferior Vena Caval Thrombosis, emedicine.com, URL: http://www.emedicine.com/med/topic2718.htm, Accessed: August 3, 2005. Major Veins

Trauma to the vena cava is usually fatal as unstoppable excessive blood loss occurs.

Additional images

File:Inferiorvenacava.png, Inferior vena cava File:Slide10bek.JPG, Inferior vena cava front view File:Inferior vena cava filter.jpg, Image of an inferior vena cava filter File:3D Medical Animation Inferior Vena Filter.jpg, Image showing an inferior vena cava filter in its position

References

External links

* - "Posterior Abdominal Wall: Tributaries to the Inferior Vena Cava" * {{Authority control Veins of the torso